Continuous melt phase manufacture of



DEFENSIVE PUBLICATION UNITED STATES PATENT OFFICE Published at the request of the applicant or owner in accordance with the Notice of Dec. 16, 1969, 869 0.G. 687. The abstracts of Defensive Publication applications are identified by distinctly numbered series and are arranged chronologically. The heading of each abstract indicates the number of pages of specification, including claims and sheets of drawings contained in the application as originally filed. The files of these applications are available to the public for inspection and reproduction may be purchased for 30 cents a sheet.

Defensive Publication applications have not been examined as to the merits of alleged invention. The Patent Ofiice makes no assertion as to the novelty of the disclosed subject matter.

PUBLISHED JUNE 23, 1970 T875,023 CONTINUOUS MELT PHASE MANUFACTURE OF LOW MOLECULAR WEIGHT POLYAMIDES M B Knowles, Harrell Julian Lewis, and Roy Clilford Stephens, all of PD. Box 511, Kingsport, Tenn.

37662 Continuation of application Ser. No. 685,734, Nov. 16,

1967. This application Dec. 12, 1969, Ser. No. 880,506 Int. Cl. C08g 20/20 US. Cl. 260-78 2 Sheets Drawing. 18 Pages Specification Water-free, low molecular weight polyamides may be prepared from aqueous solutions of polyamide salts un der superatmospheric pressure by passing a solution of a polyamide salt through a plurality of heated zones at a superatmospheric pressure while under essentially plugflow conditions, the zones being heated to a temperature sufficient to eliminate water in vapor form from the resulting low molecular weight polyamide, and the zones providing a decreasing ratio of heating surface to volume of material being treated in the direction of flow, and withdrawing a substantially water-free low molecular weight polyamide from the last of the zones at a pressure below thatof the said last zone.

June 23, 1970 l M.B.KNOIWLES ETAL T T875,023

CONTINUOUS MELT PHASE MANUFACTURE OF I LOW MOLECULAR WEIGHT POLYAMIDES Original F'uea Nov 16, 1967 FIG? 2 Sheets-Sheet 1 INVENTORS MB KNOWLES HARRELL J. LEWIS ROY C. STEPHENS Jaw ATTORNEYS M. B. KNOWLES ET AL T875,023

coumuuous MELT PHASE MANUrnuIURE 01- LOW MOLECULAR WEIGHT POLYAMIDES June 23, N10

Original Fneu NOV 16, 1967 2 Sheets- Sheet 2 a j r Y l5 T --fi I 7 7 7 F F 7 A Z Z -1... -4 K I INVENTORS MB KNOWLES HARRELL J. LEWIS ROY o STEPHENS ATTORNEYS 

